linux-kernel - Re: [PATCH v1] perf parse-events: Tidy name token matching

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Message-ID: <CAP-5=fWghT8+pBFVxn9JDbqHU9NPy9mgyT8Ee=pTdkCKxRoJgA@mail.gmail.com>
Date: Mon, 10 Feb 2025 11:23:22 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Andi Kleen <ak@...ux.intel.com>, 
	Dominique Martinet <asmadeus@...ewreck.org>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] perf parse-events: Tidy name token matching

On Thu, Jan 9, 2025 at 9:54 AM Ian Rogers <irogers@...gle.com> wrote:
>
> Prior to commit 70c90e4a6b2f ("perf parse-events: Avoid scanning PMUs
> before parsing") names (generally event names) excluded hyphen (minus)
> symbols as the formation of legacy names with hyphens was handled in
> the yacc code. That commit allowed hyphens supposedly making
> name_minus unnecessary. However, changing name_minus to name has
> issues in the term config tokens as then name ends up having priority
> over numbers and name allows matching numbers since commit
> 5ceb57990bf4 ("perf parse: Allow tracepoint names to start with digits
> "). It is also permissable for a name to match with a colon (':') in
> it when its in a config term list. To address this rename name_minus
> to term_name, make the pattern match name's except for the colon, add
> number matching into the config term region with a higher priority
> than name matching. This addresses an inconsistency and allows greater
> matching for names inside of term lists, for example, they may start
> with a number.
>
> Rename name_tag to quoted_name and update comments and helper
> functions to avoid str detecting quoted strings which was already done
> by the lexer.
>
> Signed-off-by: Ian Rogers <irogers@...gle.com>

Ping. This patch addresses name parsing inconsistencies, in particular
events may start with a number without a PMU, but not with. It also
aims to give better names to patterns than name_minus and name_tag
(with term_name and quoted_name respectively) that have drifted from
their original meaning and become to me less than intention revealing.

Thanks,
Ian